Prevents moisture or air quality problems

Moisture brings durability and air quality problems with it, and myriad green products are designed to manage it and keep it out. Given the variety of products available, we look for those that meet key performance standards and that make sense in a whole building assembly—such as vapor-permeable weather-resistive barriers that not only prevent moisture from entering the building envelope but also allow drying when the envelope gets wet.

Moisture brings durability and air quality problems with it, and myriad green products are designed to manage it and keep it out. Given the variety of products available, we look for those that meet key performance standards and that make sense in a whole building assembly—such as vapor-permeable weather-resistive barriers that not only prevent moisture from entering the building envelope but also allow drying when the envelope gets wet.

Prihoda offers a variety of permeable and impermeable textile ducts including its Recycled line of medium-weight ducts made from Repreve polyester (PET) fabric. The Repreve fabric is SCS certified for containing 100% post-consumer content and for being responsibly sourced. Recycled is available in different shapes—circular, half- and quarter round, square, triangular, and others—and in diameters from 4 to 80 inches. Recycled is REACH compliant and available in four standard colors with special orders available by request.

Testo makes a dozen models of ergonomic thermal imaging cameras for building, electrical, and mechanical analyses. The models use 160 x 120, 320 x 240, or 640 x 480 detector arrays and incorporate a digital camera so they can capture both standard and thermal images simultaneously. The Testo 875 has a thermal sensitivity of 50mK (it can distinguish temperature differences between 11.25°C and 11.75°C), and for greater sensitivity the 890-2 has 40mK and includes LED lighting and voice recording. Each model comes with a number of options.

Small Planet Workshop imports and distributes Siga air barrier tapes. Siga offers single- and double-sided tapes that range in width from 20–170 mm, and that are designed for use on the exterior and interior of wall assemblies. Pre-folded tapes are available for use in corners. Siga tapes adhere to many substrates, although Siga recommends the use of its Dockskin primer in some cases. Siga tapes contain no solvents, plasticizers, or VOCs. According to Small Planet Workshop, it is not uncommon for Siga tapes to last more than 20 years, and they have a strong reputation for durability, although GreenSpec hasn't seen hard data to support this.

Distributed in the U.S. by Four Seven Five, Pro Clima offers a full line of VOC-free, pressure-sensitive air barrier tapes designed for interior and exterior use in wall assemblies marketed toward Passive House construction projects. Most tapes are 2-3/8" (60 mm) wide, but the tapes range in width from 1"–3-3/8" (25–85 mm). Tapes with separate backing papers for use in corners are available. Pro Clima tapes adhere to a wide range of substrates, including OSB, soft wood, and masonry, although Pro Clima recommends the use of its Tescon Primer in some cases. Tescon RP primer is fluid-applied and requires no drying time before the tapes can be applied over it. According to Four Seven Five, Pro Clima tapes bond in several hours and, once dry, adhere extremely well. However, long-term testing data to support their durability is not available.

Tyroc is moisture- and mold-resistant subfloor made from a fiberglass-reinforced magnesium oxide (MgO) panel bonded to a substrate comprised of 60% post-consumer rubber and 40% post-consumer polyethylene. The molded rubber substrate has a grooved pattern to allow airflow so moisture can drain or evaporate away. Tyroc can be installed above or below grade and over cracks or pitted concrete, where appropriate, providing a vapor- and moisture-impermeable surface with excellent sound dampening, and serving as a thermal break between concrete and flooring. The 48" x 16" x ½" panels weigh 10.5 pounds and come with a limited 30-year warranty.

NovelAire’s ComfortDry 250 dehumidifier uses a desiccant wheel and hot water to reduce indoor humidity, rather than a compressor and refrigerant. The desiccant wheel rotates and adsorbs moisture from the interior and then rotates in an outdoor airstream heated by hot water coils, drying the wheel and removing the moisture to the outdoors. The system does not require condensate drainage lines, and hot water can be supplied by a variety of sources, including water heaters or solar thermal systems. ComfortDry 250 can be ducted into an existing air handler or installed as a stand-alone system. Appropriate for spaces up to 3000 ft2, it can process 300 cfm, removing 105 pints/day (80°F, 60% RH) using hot water flowing at 1–2 gallons per minute at 120°F –160°F.

AAON offers rotary Aaonaire air-to-air heat and energy recovery ventilators for commercial applications. These units are made from a polymer that has silica gel desiccant permanently imbedded, making them light, corrosion resistant, and easy to maintain, according to the company—and unlike aluminum wheels they do not require a drainpan.

Ruskin offers a variety of energy recovery ventilators (ERVs), including MiniVentilator and EnERVent units. The MiniVentilator (250–1000 cfm) is for indoor applications, whereas EnERVent and EnERVent+ (600–12,000 cfm) are for larger buildings and are available in indoor and outdoor units. EnERVent+ can be specified with options such as variable frequency blowers and CO2 sensors, and can be engineered to include a variety of heating and cooling options from gas heat to split systems.

Greenheck offers a variety of energy return ventilators for commercial applications. Models include the MiniVent-450 and -750 for use where space is limited; ERV-10, -20, -45, -and 55 (500–6,000 cfm) that can be mounted indoors on the floor or ceiling for duct access; ERV-90 and -120 (5,000–12,000 cfm) for indoor and outdoor applications; and ERVe (1,000–6,000 cfm) for outdoor installation or roofs or pads. These systems are available with a variety of options, including CO2 sensors, frost control, network interface, and more. The company also offers models that provide supplemental heating and cooling.

Multitherm is a moisture-resistant, breathable, rigid insulation and weather-resistive-barrier made from 95% wood fiber, 4% polyurethane binders, and 0.5% paraffin. Manufactured in Germany, these panels are intended for use on exterior walls under rainscreens, and are engineered with tongue and groove edges to improve weather resistance and ease installation, since the panels do not have to line up with studs. The 1-9/16"-thick, 43.3"-long, 31.5"-wide panels have an R-value of 3.7 per inch (R-5.5 per panel) and a perm rating of 27. Custom sizes are also available.

Air Pohoda offers high-performance HRVs and ERVs, including the Ultima 240E iERV (intelligent energy-recovery ventilator). The Ultima 240E operates at 95% efficiency and is the first ERV with adjustable humidity control. These units can provide 240 cfm of ventilation using a triangular-shaped core with channels that capture the condensate so the moisture can either be drained away or directed back into the living space. Because the humidity can be controlled, the 240E can operate in any climate; the core does not contain perforations so dust will not clog the unit over time; and the unit does not freeze down to 10°F and does not require a preheater. It also uses an electronically commutated motor (ECM) so it is very efficient, and six-inch ducts to deliver good airflow. These units come with a 25-year warranty. The company also offers 240 and 60 cfm HRVs, both of which use ECMs.

Airguard produces a wide range of air filtration products with MERV 13 (80%–85%) and higher efficiency ratings. It offers a variety of rigid-cell filters composed of micro glass or synthetic media fibers, as well as multiple extended surface pocket filters. The Multi-Guard Pocket filter is electrostatically enhanced for higher initial efficiency and has gradient density fiber for dust holding capacity. Airguard also offers two HEPA filters: Microguard, which is available in a wood and metal construction, and Micropleat, which is made of ultrafine microglass paper media. Both operate at up to 99.999% efficiency on 0.3 micrometer particles.

Tri-Dim offers air filters from MERV 13 and higher, as well as HEPA/ULPA in a range of types, sizes, and depths, including pleated, thin line, V-cell, rigid box, and bag in fiberglass and synthetic media. Packaged prefilters, roll media, and bulk pads are also available.

Majvest, from the Swiss company SIGA, is a high-performance weather-resistive barrier for use on exterior walls. The half-millimeter-thick WRB effectively blocks rain and wind, yet provides high vapor permeability with 68 perms (U.S.). The product ships in 3-meter (9.8') rolls 50 m (164') long. Edges should be taped with high-performance tapes, also made by SIGA. SIGA WRBs and tapes are distributed in the U.S. by Small Planet Workshop in Olympia, Washington.